The present invention relates to photomask lithography, and more specifically, to systems and methods for sleeving of mask shapes implementing multiple lithographic systems.
In photolithography, masks are implemented to pattern devices on semiconductor wafers. Masks are fabricated to define patterns for the devices. Masks are typically fabricated by forming blanks with a patterned opaque film. For example, quartz blanks can be coated with a suitable opaque film such as chrome or molybdenum-silicide (MoSi). Photoresist is implemented to pattern the opaque film and currently, electron-beam (e-beam) writers are implemented to expose the resist to form the patterns. Prior to the advent of e-beam writers, optical writers were implemented and typically operated lower current density and higher wavelengths, such as 256-365 nm. For the lithographic step of transferring these mask patterns to wafers, the accuracy and crispness of outer edges of the shapes on the masks are important because the outer edges define the edges of shapes transferred from the masks to the wafers. Center regions typically function to block light, but the edges define size, and thus influence size control of the device features. The cost of e-beam writer is proportional to the time it is implemented. Write times for entire masks can be six to twenty four hours. Therefore, the longer the e-beam writer is used, the more expensive the costs of the masks. What is needed is a system and method to reduce the time needed to use e-beam writers for patterning photomasks while maintaining the size control and other critical dimensions of masks.